title: Left ventricular dyssynchrony resulting from right ventricular apical pacing: relevance of baseline assessment.
abstract: OBJECTIVE
  Evaluation of left ventricular (LV) dyssynchrony in patients undergoing short-term right ventricular apical (RVA) pacing and correlation with baseline echocardiographic and clinical characteristics.
  
  
  BACKGROUND
  RVA pacing causes abnormal ventricular depolarization that may lead to mechanical LV dyssynchrony. The relationships between pacing-induced LV dyssynchrony and baseline echocardiographic and clinical variables have not been fully clarified.
  
  
  METHODS
  Tissue Doppler echocardiography was performed in 153 patients before and after RVA pacing. LV dyssynchrony was measured by the time between the shortest and longest electromechanical delays in the five basal LV segments (intra-LV). The prevalence and degree of LV dyssynchrony after RVA pacing was evaluated in three groups: baseline LV ejection fraction (LVEF) <35%, 35-55%, and >or=55%. The intrapatient effect of RVA pacing was determined as the percent increase in intra-LV value (Deltaintra-LV%). The pacing-induced intra-LV was correlated with baseline variables.
  
  
  RESULTS
  The prevalence and degree of LV dyssynchrony after RVA pacing was significantly higher in patients with lower LVEF (P < 0.001). DeltaIntra-LV% was inversely correlated with baseline intra-LV and LVEF (B =-2.6, B =-4.2, P < 0.001). Baseline intra-LV and LV end-systolic volume correlated positively with intra-LV after RVA pacing (B = 0.49, B = 0.6, P < 0.001), whereas LVEF showed an inverse correlation.
  
  
  CONCLUSIONS
  The degree of LV dyssynchrony induced by RVA is variable. Patients with higher baseline LV dyssynchrony, more dilated LV, and more depressed LVEF showed a higher degree of LV dyssynchrony during pacing. These findings may assume importance in predicting the risk of heart failure in pacemaker patients.
authors.affiliation: Department of Cardiology, Rovigo General Hospital, Rovigo, Italy. gian.past@libero.it
authors.forename: Gianni
authors.initials: G
authors.lastname: Pastore
authors.forename: Franco
authors.initials: F
authors.lastname: Noventa
authors.forename: Piergiuseppe
authors.initials: P
authors.lastname: Piovesana
authors.forename: Roberto
authors.initials: R
authors.lastname: Cazzin
authors.forename: Silvio
authors.initials: S
authors.lastname: Aggio
authors.forename: Roberto
authors.initials: R
authors.lastname: Verlato
authors.forename: Francesco
authors.initials: F
authors.lastname: Zanon
authors.forename: Enrico
authors.initials: E
authors.lastname: Baracca
authors.forename: Loris
authors.initials: L
authors.lastname: Roncon
authors.forename: Luigi
authors.initials: L
authors.lastname: Padeletti
authors.forename: S Serge
authors.initials: SS
authors.lastname: Barold
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000706:statistics & numerical data*; D015897:Comorbidity; D005260:Female; D006801:Humans; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D008297:Male; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000453:epidemiology*; D018497:Ventricular Dysfunction, Right / Q000453:epidemiology* / Q000517:prevention & control*